It is known in wireless communication systems to provide data communication services such as Internet access and local services through license exempt radio resource bandwidths using wireless local-area network (WLAN) technologies such as Wi-Fi and Wi-Fi Direct, which are based on Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards or using wireless personal area network (WPAN) technologies such as Bluetooth and Ultra Wideband technologies. WLAN and WPAN technologies allow for higher data rates and lower energy consumption by exploiting short distances between a transmitter and receiver. However, Wi-Fi and Bluetooth are susceptible to sources interference from other communications in the unlicensed band and there is no network-based interference management available for these technologies. In the third generation partnership project (3GPP) long term evolution (LTE) and LTE-Advanced (LTE-A) licensed radio band, femtocells, picocells and relays also make use of short distances between transmitter and receiver to perform efficient communication with user equipments (UEs), but these systems require that the data communications pass through the picocell/femtocell base station or relay rather than passing directly between transmitting and receiving UEs and they also require a backhaul connection to an LTE or LTE-A eNodeB of a wireless cellular system.
D2D communications utilizing the LTE/LTE-A spectrum offer the possibility of extending the maximum transmission distance (possibly up to around 1000 m) relative to technologies such as Bluetooth (10-100 m approximate range) and Wi-Fi direct (200 m approximate range) and can reduce the costs and scalability problems potentially associated with the backhaul connection required for picocell/femtocell/relay infrastructure-based networks. D2D communications according to the present technique may also comprise Peer-to-Peer (P2P) communications involving direct communication between network entities or wireless equipments at the same hierarchical level of the wireless network, for example direct communications between picocells, femtocells and relays as well as direct communications between wireless devices such as UEs. A wireless equipment includes at least a UE, a picocell, a femtocell and a relay node.
D2D/P2P communications allow offloading of some network traffic, but there is a need to carefully manage interference arising from the D2D layer to protect both cellular and D2D communication links from in-band emission interference. In-band emission interference corresponds to leakage in a given transmitter within the channel bandwidth, and the resulting leakage can interfere with other transmitters. Out-of-band interference originates from a neighboring transmitter configured to transmit in a different frequency bandwidth, but which still produces energy in the frequency bandwidth of the given transmitter. In-band emission, which can give rise to in-band emission interference can degrade performance of D2D communications, so there is a requirement to control in-band emission.